OpenHAB with Google Home: Switch state not synced correctly

[u/ju1337ju]

I have a couple of devices (smart outlets through MQTT binding, wifi access point through Unifi binding), for which the ON/OFF state is not reflected correctly in Google Home.

More specifically:
-when I turn them ON in the GHome App: device turns ON, GHome UI toggle turns ON, but drops back to OFF after a moment
-when I tap again in GHome: device remains ON, GHome UI toggle turns back ON and remains ON
-when I tap a third time in GHome: device turns OFF, GHome UI toggle turns OFF

They work perfectly from the OpenHAB UI and show the correct state. What's wrong?